<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<input type="text" id="v1">
<input type="text" id="v2">
<input type="button" id="bt" value="=">
<input type="text" id="res">

</body>
<script src="build.js"></script>
</html>